The phosphotransferase system (hereinafter sometimes also referred to as “PTS”) is a system for mediating sugar uptake and phosphorylation that is observed in many types of bacteria. Certain types of sugars are taken into cells as being phosphorylated by three components, i.e., protein EI, HPr and EII, whereby the components relay and transfer phosphoric acid derived from phosphoenolpyruvic acid to the sugars. Sugars whose cellular uptake is mediated by the PTS are called PTS sugars. It is known that when the PTS is impaired, it becomes impossible to grow on a minimal medium containing a PTS sugar as the sole carbon source (see Non-patent Literature (NPL) 1).
There are other sugars, called non-PTS sugars, which are taken into cells by a permease, not via the PTS, and then phosphorylated by a kinase. Glucose, which is generally used in fermentative production using a microorganism, is classified as a PTS sugar in many types of microorganisms. Accordingly, if a PTS-deficient microorganism belonging to the genus Corynebacterium, such as Corynebacterium glutamicum, Escherichia coli or the like, is used for fermentative production using glucose as a carbon source, the microorganism cannot utilize glucose, thus resulting in poor growth and low productivity.
Some E. coli strains have been reported to have a PTS sugar uptake system other than the PTS. For example, Non-Patent Literature 2 (NPL 2) discloses an E. coli strain which, as a result of a mutation of a galactose permease gene, has become able to grow in a glucose medium. However, such a system is unknown in microorganisms belonging to coryneform bacteria.
Among ORFs on the chromosomal DNA of Corynebacterium glutamicum, both Cgl0181 (NCgl0178) and Cgl3058 (NCgl2953) have been reported to encode proteins involved in myo-inositol transport (Non-Patent Document 3). However, it is unknown what level of glucose uptake ability is imparted to a microorganism whose expression of genes encoding these proteins has been enhanced, or what effect is given to the useful substance productivity of a microorganism by the enhanced expression of these proteins.